A liquid crystal display (LCD) that employs an in-plane switching (IPS) sub-pixel circuit is presently considered state-of-the-art technology. IPS LCD has benefits in viewing angle and operational speed compared to a more traditional vertical alignment (VA) based LCD sub-pixel circuit. The primary distinction between IPS and VA LCD sub-pixel circuits is the relative location of the two electrodes (i.e., sub-pixel electrodes) between which an electric field is applied to polarize a liquid crystal material located between the two electrodes. The extent to which the liquid crystal material is polarized controls the amount of light that is transmitted through the backplane. The control of light transmission through the backplane is the means through which a digital image is created on an LCD. IPS based sub-pixel circuits have both electrodes located on one substrate (i.e., the backplane), whereas VA based sub-pixel circuits have one electrode on the backplane and one electrode on a second substrate (i.e., the color filter, CF). Present IPS LCD technology employs a thin-film transistor (TFT), located on the backplane, to control the magnitude of the electric field applied between sub-pixel electrodes that, in turn, controls the digital image on the IPS LCD.
The LCD backplane, which is a glass substrate onto which active devices, conducting layers and insulating layers are fabricated, controls an image on a liquid crystal display through precisely polarizing a liquid crystal material located between the backplane and another layer of glass. The second layer of glass, in certain embodiments known as color filter glass (CF), is the location of color filters, one per sub-pixel, used to create color images. Presently, the preferred backplane active device is the thin-film transistor (TFT), which is a semiconductor based device comprised of sequentially deposited and patterned thin-film layers. Thin-film semiconductor materials used in TFTs have many limitations, including low carrier mobility, light and temperature sensitivity, and fabrication complexities, which create performance and manufacturing cost issues. Thus, new devices which overcome such limitations, such as those disclosed herein, represent an advance in the state of the art.